This invention relates to drive mechanisms for powering the drive wheels of vehicles. More particularly, it provides a unique drive mechanism for powering the drive wheel of a vehicle utilizing motors driven at a substantially constant speed at which efficiency of performance is optimized.
With the energy crisis confronting the world, it is imperative to produce vehicles which are as efficient and consume as little fuel and emit as few combustion by-products as possible. The traditional internal combustion engine as heretofore used in drive mechanisms for vehicles is notoriously inefficient, particularly because it is typically operated over a wide range of speeds within which the efficiency of performance varies considerably. The present invention utilizes a drive shaft which is driven at a constant speed, so that the efficiency of power development may be optimized and emissions minimized. The constant speed drive shaft is selectively coupled through a unique transaxle unit to provide for the driving of a vehicle wheel at variable speeds. In particular, selective braking of a control shaft in the transaxle unit provides the desired coupling between the constant speed drive shaft and the drive wheel of the vehicle.
In a presently preferred embodiment of the invention, an internal combustion engine is regulated to run at a constant speed. The engine drives an electric generator which in turn drives an electric motor. The motor is driven at constant speed, and is coupled through a conventional clutch and flywheel mechanism to the transaxle unit mentioned above. The transaxle unit includes power input and output shafts as well as a control shaft. Depending upon the selective braking of the control shaft, the power output shaft is caused to rotate during rotation of the power input shaft. Such selective braking of the control shaft to control the vehicle speed is achieved, for example, by actuation of the accelerator pedal in an automobile which is coupled to the braking mechanism for the transaxle control shaft. The accelerator pedal is not used as a control mechanism for the supply of fuel as is the case with automobiles presently in use. As presently preferred, a single internal combustion engine driving a single electric generator may be utilized to power a plurality of electric motors each driving an individual one of the drive wheels through an individual transaxle mechanism associated with that wheel. Alternatively, a single transaxle unit may be utilized to power a plurality of drive wheels through a conventional differential mechansim.
The following patents are representative of the state of the art.
______________________________________ U.S. Patent No. Issue Date Inventor ______________________________________ 3,260,134 July 12, 1966 Bowen et al 3,352,373 Nov. 14, 1967 Tuck 3,375,737 April 2, 1968 Holtan 3,525,874 Aug. 25, 1970 Toy 3,530,356 Sept. 22, 1970 Aronson 3,543,873 Dec. 1, 1970 Toy 3,656,202 Feb. 23, 1971 Evans 3,713,504 Jan. 30, 1973 Shimer et al 3,861,484 Jan. 21, 1975 Joslin ______________________________________